reminders: problem set 2: due today - university...
TRANSCRIPT
REMINDERS: Problem Set 2: Due TODAY Midterm 1: Wednesday, Feb 5
- Lecture material covering chapters 1-5 - Multiple Choice, Short Answers, Definitions - Practice midterm will be on course website - Closed-book, no notes, no calculator. - No scantron or blue book necessary
UPCOMING REVIEW SESSION:
- Tuesday, Feb 4, 6:30-8:00pm in HSS 1330
2. WHAT CAUSES AN AIR PARCEL TO INITIALLY RISE?
A. Surface heating leading to Convection
B. Topography (Mountains) = Orographic Uplift
2. WHAT CAUSES AN AIR PARCEL TO INITIALLY RISE?
A. Surface heating leading to Convection
B. Topography (Mountains) = Orographic Uplift
C. Ascent due to Convergence
2. WHAT CAUSES AN AIR PARCEL TO INITIALLY RISE?
A. Surface heating leading to Convection
B. Topography (Mountains) = Orographic Uplift
C. Ascent due to Convergence
D. Uplift along Weather Fronts
Wind
Windward Side Leeward Side
Clicker Question
Mountain
Which side of the mountain would generally receive more precipitation? (A) Windward
(B) Leeward
(C) Both sides would receive equal amounts
Set Frequency to "AD"
Wind
Windward Side Leeward Side
Clicker Question
Mountain
Which side of the mountain would generally receive more precipitation? (A) Windward
(B) Leeward
(C) Both sides would receive equal amounts
Set Frequency to "AD"
Wind
Windward Side Leeward Side
Mountain
On Windward side: - rising air - temperature decreases - relative humidity increases - may get to saturation => clouds and maybe precipitation
On Leeward side - sinking air - temperature increases - relative humidity decreases - Clouds evaporate => little or no precipitation
Wind
Windward Side Leeward Side
Mountain
On Windward side: - rising air - temperature decreases - relative humidity increases - may get to saturation => clouds and maybe precipitation
On Leeward side - sinking air - temperature increases - relative humidity decreases - Clouds evaporate => little or no precipitation
Mountain range often produce RAIN SHADOW on Leeward Side
Region of reduced precipitation
Clicker Question
The collision-coalescence process is most efficient when: (A) all the cloud droplets are small (B) all the cloud droplets are large (C) there is a mix of small and large cloud droplets
Set Frequency to "AD"
Clicker Question
The collision-coalescence process is most efficient when: (A) all the cloud droplets are small (B) all the cloud droplets are large (C) there is a mix of small and large cloud droplets
Set Frequency to "AD"
Clicker Question
In general, which cloud would you expect to produce larger rain drops through the collision-coalescence process? (A) cumulus cloud (B) stratus cloud (C) cirrus cloud
Set Frequency to "AD"
Clicker Question
In general, which cloud would you expect to produce larger rain drops through the collision-coalescence process? (A) cumulus cloud (B) stratus cloud (C) cirrus cloud
Set Frequency to "AD"
Cloud Droplet Growth Processes: 1) Collision-Coalescence
- warmer clouds, liquid water only - different size drops fall at different speeds
2) Ice-Crystal Process
- colder clouds with both liquid water and ice
T=0°C (Freezing level)
T=-40°C
Liquid Only
Supercooled Liquid and Ice
Ice Only
Surface
Tall Cumulonimbus Cloud
This region is where Ice-Crystal Process occurs
Question: How can liquid water exist below freezing point? - need freezing nuclei for liquid water to freeze into ice crystal if temperature is between 0 and -40°C. - similar idea as cloud condensation nuclei, except the structure of freezing nuclei must be similar to the structure of ice crystal ==> As a result, much fewer freezing nuclei in atmosphere compared to number of cloud condensation nuclei
In Equilibrium: Condensation = Evaporation
Liquid Drop and Water Vapor
Ice Crystal and Water Vapor
More Water Vapor Around Liquid Drop
Less Water Vapor Around Ice Crystal
water vapor liquid water ice crystal
Now, put Liquid Drop and Ice Crystal Together
Now more water vapor around Ice Crystal => Vapor condenses on Ice
water vapor liquid water ice crystal
Now, put Liquid Drop and Ice Crystal Together
Now more water vapor around Ice Crystal => Vapor condenses on Ice
water vapor liquid water ice crystal
Now, put Liquid Drop and Ice Crystal Together
Now more water vapor around Ice Crystal => Vapor condenses on Ice As water vapor decreases => Liquid water evaporates from drops
water vapor liquid water ice crystal
Now, put Liquid Drop and Ice Crystal Together
water vapor liquid water ice crystal
Now more water vapor around Ice Crystal => Vapor condenses on Ice As water vapor decreases => Liquid water evaporates from drops
=> Ice Crystal Grows => Liquid Drop Shrinks
Freezing Rain - rain refreezes on contact with surface - shallow cold layer near surface
Sleet - rain refreezes before hitting surface - deeper cold layer near surface